Which Is the Best Substrate to Regenerate? A Comparative Pot Experiment for Tree Seedling Growth on Decayed Wood and in Soil
Round 1
Reviewer 1 Report
Major comments:
This study focuses biotic and abiotic factors of wood decay type (white-rot and brown-rot) on the seedling growth of Japanese four tree species using pots experiment. The focus is unique and interesting, but it is difficult to provide enough explanation based on the data obtained. This is likely due to the experimental periods, water, and nutrient conditions to reproduce the field conditions in the pot experiment.
Mycorrhizal colonization for cedar and cypress were higher in the unsterilized soil, but the seedlings grown in the sterilized soil without AM propagules had better biomass and shoot growth. This contradiction is probably due to the fact that nutrients were generally higher in the sterilized soil, except for NO3. These two species are late-successional tree species. Gehring (2003, Plant Ecol 167) mentions that late-successional species have a slower response to AM-induced growth. For this reason, I suppose that the six-month experimental period was not enough to make a difference between the compartment.
Even if more ECM fungal OTUs were detected in the substrate, their activity may have been limited because they were not reflected in the field conditions. For example, the watering was done once every 4 days, but the water holding capacity of soil and wood must be different. This is related to the fact that Cenococcum geophilum was a priority in the ECM tips.
Because the nutrient concentrations differ greatly between sterilized and unsterilized substrates (Fig. 1), it would be difficult to discuss the biotic factors without these large differences. Rather, it would be better to sort out the differences in growth responses within the sterilized and unsterilized conditions, respectively.
Minor comments:
2.4. Chemical roperties of substrates
Did the nutrient concentrations for each substrate measured after mixing vermiculite?
Table 1: Caption for abrreviation in Functional categories are needed.
Table 3: OTU_867 Inocybe sp. is also ectomycorrhizal
Fig.4: arbuscul > arbuscule
Author Response
Please see attached file.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Fukasawa and Kitabatake's paper is focused on determining the best substrate for growing tree seedlings.
It is very difficult to comment on specifics as the paper was without line numbering.
Abstract:
The abstract needs to be rewritten for clarity. It is difficult to follow at the moment. You mentioned strongly that fungal dna barcoding showed that wood substrates lack mycorrhizal fungal. That's a very strong statement. It is possible mycorrhizal fungi were not detected because of the primers you used, your bioinformatics method, etc
Introduction:
Major parts need to be rewritten for clarity. For instance, in your hypothesis, what you wrote currently means that C. japonica and C. obtuse are mycorrhizal species whereas you want to write that they are tree species that form mycorrhizal associations.
Materials and Methods:
This entire section is very difficult to follow and one cannot really see clearly what you did. This needs to be rewritten. If you had line numbering, there are numerous points I would have raised
Results and Discussion:
Please present this in a clear and concise manner
Author Response
Please see attached file.
Author Response File: Author Response.docx
Reviewer 3 Report
Here is the review of the paper titled "Which is the best substrate to regenerate? A comparative pot experiment for tree seedling growth on decayed wood and soil" written by Yu Fukasawa and Hiroyuki Kitabatake.
The paper would be suitable for publication in Forests journal after implementing my suggestions in the attached revised manuscript pdf.
Best, Reviewer
Comments for author File: 
Comments.pdf
Author Response
Please see attached file.
Author Response File: Author Response.docx
